MySQL UTF8 varchar column size

MySQL documentation says that since 5.0, varchar lengths refer to character units, not bytes. However, I recently came across an issue where I was getting truncated data warnings when inserting values that should have fit into the varchar column it was designated.

I replicated this issue with a simple table in v5.1

mysql> show create table test\G
 *************************** 1. row ***************************
 Table: test
 Create Table: CREATE TABLE `test` (
   `string` varchar(10) DEFAULT NULL
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8
 1 row in set (0.00 sec)
 

I then inserted multiple 10 characters values with differing amounts of UTF8 characters

mysql> insert into test (string) values 
     -> ('abcdefghij'),
     -> ('ãáéíçãáéíç'),
     -> ('ãáéíç67890'),
     -> ('éíç4567890'),
     -> ('íç34567890');
 Query OK, 5 rows affected, 4 warnings (0.06 sec)
 Records: 5  Duplicates: 0  Warnings: 4
 
 mysql> show warnings;
 +---------+------+---------------------------------------------+
 | Level   | Code | Message                                     |
 +---------+------+---------------------------------------------+
 | Warning | 1265 | Data truncated for column 'string' at row 2 |
 | Warning | 1265 | Data truncated for column 'string' at row 3 |
 | Warning | 1265 | Data truncated for column 'string' at row 4 |
 | Warning | 1265 | Data truncated for column 'string' at row 5 |
 +---------+------+---------------------------------------------+
 
 mysql> select * from test;
 +------------+
 | string     |
 +------------+
 | abcdefghij |
 | ãáéíç |
 | ãáéíç |
 | éíç4567 |
 | íç345678 |
 +------------+
 5 rows in set (0.00 sec)
 

I think that this shows that the varchar size is still defined in bytes or at least, is not accurate in character units.

The question is, am I understanding the documentation correctly and is this a bug? Or am I misinterpreting the documentation?

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